The present invention relates generally to a stabilizer for a magnetic recording and/or reproducing apparatus, such as a video tape recorder (VTR). More specifically, the invention relates to an improved structure of a stabilizer for damping vibration of the magnetic tape in a VTR.
In general, stability of magnetic tape travel motion in a VTR influences wow and flutter of reproducing audio signals and fluctuation of control signals causes jitter. To achieve the desired stability, some VTRs have an impedance roller for stabilizing the travel of the magnetic tape.
When a magnetic tape cassette is loaded into a conventional type VTR, a pivotal closure lid is automatically pivoted away from the front surface of the tape cassette to expose the magnetic tape, and a set of tape guide posts provided in the VTR guide the exposed tape onto a rotary head drum so as to be wrapped helically about at least a portion of the periphery of the drum. Another section of the tape between two of the guide posts is brought into engagement with a full width erase head.
During reproduction or recording, the tape is withdrawn from the supply reel table in the tape cassette and driven across the surfaces of the guide posts, the erase head and the drum. Longitudinal vibration of the tape tends to be generated at the points of contact between the tape and the erase head and guide post which causes jitter or fluctuation of the video signal, thereby producing a fluctuating picture. Particularly, when a improved magnetic tape having a high grade magnetic layer and a mirror surface film layer on a back surface thereof, such as a metal tape is used, the longitudinal vibrations of the tape tend to be much greater than with normal tape. The reason is that the tape section contacting the surface of the full width erase head and the guide posts located at the supply reel table side tends to stick. This is due to the relatively high friction coefficient of such tape. Thus, so-called "stick-slip" at contact surfaces generates longitudinal vibrations in the tape which induce jitter in the signal. It will be appreciated that reduction of the longitudinal vibration of the tape on the periphery of the rotary head drum is important in order to record or reproduce a high quality picture.
Therefore, while there is no very serious problem when a normal type magnetic tape is used in a conventional VTR, in order to obtain a high quality picture a VTR which is compatible with high quality tape comprising an effective means for attenuation of the longitudinal vibration of the tape generated at the erase head etc. located in the vicinity of the rotary head drum has been desired.